In the course of manufacturing Organic Light-Emitting Diode (OLED) devices, film coating by evaporation is one of the most critical steps, because display effect and lifespan of OLED devices largely depend on how well the uniformity and evenness of thickness of film coating are. As a result, the uniformity and evenness of thickness of film coating are always important factors to be controlled during the manufacturing process. However, in the case of film coating with larger area by evaporation, it is too challenging to guarantee a prefect uniformity and evenness in terms of thickness for film coating, due to limits brought by evaporation source and material themselves.